Hydraulic pumps are used to pump fluids from one location to another. For example, hydraulic pumps may be used in hydraulic fracturing to pump fracturing fluid (“fracking fluid”) into a well and beneath the surface of the earth to extract resources such as natural gas from within the earth. In another example, cement pumps can be used for a variety of other pressure pumping services, such as pumping cement to a location where the cement is used to form a structure, provide an anchor or secure a casing of a bore that goes into a well, and the like. Other types of pumps, such as mud pumps that carry lubricant to flush drill cuttings from a well, also may be used.
Known systems used to power these hydraulic pumps include mechanical transmissions that mechanically couple a prime mover with the hydraulic pumps. For example, some known systems include a diesel engine as the prime mover, which creates rotational power or movement. This power or movement is transferred through a manual or automatic mechanical and/or hydraulic transmission that includes one or more shafts, gears, pinions, or the like, that are coupled with the diesel engine or other prime mover. The mechanical transmission changes the speed and/or torque of the rotational movement created by the prime mover.
The mechanical transmission also is mechanically coupled with the hydraulic pump by one or more gears, shafts, pinions, or the like. The rotational movement from the prime mover that is modified by the mechanical transmission is provided to the hydraulic pump, such as by coupling an output shaft of the mechanical transmission with the pump to cause the pump to reciprocate (or other means of positive displacement) and force a fluid from one location to another (e.g., into a well).
At least one shortcoming of using such a mechanical transmission is that the mechanical components of the transmission may be limited in how much power can be transferred from the prime mover to the hydraulic pump. Some known mechanical transmissions are limited in the power that can be provided to the hydraulic pumps due to design limitations on the gears, pinions, shafts, torque converters, and the like, that are restricted based upon available space for the mechanical transmissions, gear ratios of the mechanical transmissions, or the like. For example, some known mechanical transmissions that couple a shaft connected with a diesel engine to one or more gears for powering a hydraulic pump may be able to provide up to 2250 or 2500 horsepower (HP), but not in excess of these amounts. The volume of fluid that is pumped by the hydraulic pump (e.g., the fluid flow) is based on this HP that is used to power the hydraulic pump. As a result, the volume of fluid that can be pumped by the hydraulic pump can be limited.
One attempted solution to increase the amount of fluid flow that is provided by the hydraulic pumps is to fluidly couple several hydraulic pumps that are powered by different systems together so that the cumulative flow of the fluid that is generated by the hydraulic pumps is increased. Given the large sizes of the mechanical transmissions and the limits on power that can be provided by the mechanical transmissions, however, a relatively large number of such mechanical transmissions and the vehicles that carry the transmissions may be needed to supply adequate power to the hydraulic pumps. As a result, many of these vehicles, transmissions, and pumps may need to be located in relatively close proximity at a pumping location (e.g., wellhead) which can create a large degree of congestion at or near the pumping location.